One of the trace-summary tests fails on some systems due to
the test canonifier script not working correctly on those systems.
Branch "topic/dnthayer/ticket1730" in the trace-summary repo contains
a fix for this issue.
Out of curiosity - which systems did this fail on with the old syntax?
FreeBSD and OS X, due to differences in the way "sed" behaves.
I forgot to mention that this issue has nothing to do with Python 3.